Use of a Tracer Gas Technique to Study Mixing in a Low Speed Turbine

A method of using a flame ionization detector to study the movement of air containing a small concentration of ethylene is described. Ethylene is chosen because it has almost the same density as air so buoyancy effects are negligible. The technique is applied to flow in a bent duct and in a low speed air turbine. In both cases large scale migrations of the end wall boundary layers onto the suction surfaces are observed. However, in the turbine the span wise movement and mixing of the flow at mid-span is remarkably small.